>>96353418
I feel like it's something she's been aware of, with her self-perception being her Idolon rather than the her in the real world. Her experience with the march is what I imagine deepened her connection to the idea world to an unhealthy level.
Part of her understands using it as an extension of her duties as a shrine maiden, while the other simply uses it escape from reality when she feels her soul can no longer bear it's weight.

>>96374185
I think of Renka as primarily being an accessory to others.

Renka's side plot in the Census club debacle is Momo convincing her to be a silent bystander to Alyona's actions, but on a deeper a level I see this as grounding her more in reality. While there are multiple factors at play for her isolation, a significant one is that she simply doesn't feel at home in reality. As more and more supernatural elements come into play I imagine her being pulled between both worlds, both literally and metaphorically. Eventually, her withdrawal into herself turns into hiding herself away in her slice of the idea world.

It would depend on others being involved in When Children go Marching, but having the past resurface and explore through it something I've been thinking about.